1. Technical Field
The present invention relates, in general, to a display apparatus and controlling method thereof and, more particularly, to a display apparatus and controlling method thereof in which electric power consumption can be effectively minimized in a power saving mode by controlling a unified scaler chip.
2. Description of the Related Art
A computer system comprises a computer having a storage unit, such as a hard disk drive, a memory, a main board on which a video card is mounted, and a power supply unit supplying electric power to the storage unit and to the main board. A display apparatus is connected to the computer and receives a video signal from the video card of the computer so as to display a picture thereon.
To minimize electric power consumption in the computer system, a display power management system (DPMS) and method have been employed to suspend operations of chips in connection with video signal processing in the display apparatus when data is not inputted from the video card for a predetermined period of time.
In the display apparatus, the DPMS and related method include three modes according to the input of horizontal (H) and vertical (V) synchronous signals generated by the video card. The three modes are a standby mode in which the H synchronous signal is not inputted, a suspending mode in which the V synchronous signal is not inputted, and a complete power saving mode in which both the H and V synchronous signals are not inputted.
The display apparatus comprises a D-sub connector port through which analog red/green/blue (R/G/B) video signals and H/V synchronous signals are received from the video card of the computer, an analog/digital (A/D) converter for converting the analog R/G/B video signals from the D-sub connector port into digital signals, a liquid crystal display (LCD) panel for displaying a picture thereon, and a panel driver driving the LCD panel. The display apparatus further comprises a digital video interface (DVI) connector port through which digital video signals are received, a transition minimized differential signaling (TMDS) part for decoding compressed digital video signals from the DVI connector port into R/G/B video signals and H/V synchronous signals, and a scaler for processing the synchronous signals and the digital R/G/B video signals received from the A/D converter and the TMDS part according to the size of the LCD panel, and for outputting them to an LCD panel driver.
Thus, in the display apparatus, the three modes of the DPMS method are determined according to synchronous signals received from the D-sub connector port and the TMDS part in order to suspend operation of each component, thereby minimizing electric power consumption.
Recently, a unified scaler chip having the functions of the A/D converter, the TMDS part and the scaler of the display apparatus has been developed. However, in the display apparatus having the unified scaler chip, the type of synchronous signal is directly determined by the D-sub connector port in the case of the input of analog H/V synchronous signals, but it is indirectly determined by the unified scaler chip in the case of the input of digital video signals. Thus, electric power must be always supplied to the unified scaler chip, and this makes it difficult to meet the DPMS standard.
The following are considered to be generally pertinent to the present invention but are burdened by the disadvantages set forth above: U.S. Pat. No. 6,016,071 to Shay, entitled INTERNAL SOURCE CLOCK GENERATION CIRCUIT FOR USE WITH POWER MANAGEMENT, issued on Jan. 18, 2000; U.S. Pat. No. 6,021,501 to Shay, entitled CLOCK ENABLE/DISABLE CIRCUIT OF POWER MANAGEMENT SYSTEM, issued on Feb. 1, 2000; U.S. Pat. No. 6,052,792 to Mensch Jr., entitled POWER MANAGEMENT AND PROGRAM EXECUTION LOCATION MANAGEMENT SYSTEM FOR CMOS MICROCOMPUTER, issued on Apr. 18, 2000; U.S. Pat. No. 6,115,032 to Kotha et al., entitled CRT TO FPD CONVERSION PROTECTION APPARATUS AND METHOD, issued on Sep. 5, 2000; Korean Patent Publication No. 2000-65497 to Joon-Hee Kim et al., entitled A CIRCUIT FOR OPERATING LCD MONITOR, published on 15, Nov. 2000; Japanese Patent Publication No. 2000-298536 to Fujimoto, entitled INFORMATION PROCESSOR, published on Oct. 24, 2000; and Japanese Patent Publication No. 2000-347640 to Yamada, entitled ELECTRONIC DEVICE, DISPLAY SYSTEM, AND METHOD THEREOF, published on Dec. 15, 2000.